The mupen64plus board is a subforum of this forum (which is for Mupen64).
Also: a very small amount of investigation (like perhaps reading the project homepage) would tell you two things:
1) mupen64plus was engineered around linux, and is very stable on it.
2) No, at current there is no PPC support, and will not be for some time.
If you think you can write a recompiler for PPC architecture, then feel free to add something to the project.
If not, don't feel like you have the right to demand such a thing from it.
It's not a simple "oh, I forgot to set 'workOnPPC' to true, silly me".
But it sounds like you should just go back to playing what games the PS3 already has to offer.